Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/lestrrat-go/jwx/guidenpx skills add lestrrat-go/jwx --skill guidegit clone --depth 1 https://github.com/lestrrat-go/jwxWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/lestrrat-go/jwx/guide)<a href="https://agentmods.dev/skills/lestrrat-go/jwx/guide"><img src="https://agentmods.dev/badge/skills/lestrrat-go/jwx/guide.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00061 | $0.04712 |
| Opus 5 | $0.00030 | $0.02356 |
| Sonnet 5 | $0.00012 | $0.00942 |
| Haiku 4.5 | $0.00006 | $0.00471 |
Grade A, and why
jwx-guide-v4 scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 314 lines — stays where its author put it; the contents beside it link to each section on GitHub.
jwx-guide-v4
This skill helps you assist Go developers who are using github.com/lestrrat-go/jwx/v4 in their own projects. It is scoped to v4 only — for v3 or v2, install the corresponding jwx-dev-v3 / jwx-dev-v2 plugin.
Where to look things up
You will not have this repository checked out. To verify an API claim before answering, use these sources, in order of preference:
- Go module cache — if the user's project depends on jwx, the source is on disk:
This directory contains the full source tree includingecho "$(go env GOMODCACHE)/github.com/lestrrat-go/jwx/v4@$(go list -m -f '{{.Version}}' github.com/lestrrat-go/jwx/v4)"docs/,jwt/,jws/,jwe/,jwk/,jwa/. - pkg.go.dev — canonical API reference for any exported symbol:
https://pkg.go.dev/github.com/lestrrat-go/jwx/v4https://pkg.go.dev/github.com/lestrrat-go/jwx/v4/jwt(etc. per subpackage)
- GitHub — narrative documentation lives at the repo:
https://github.com/lestrrat-go/jwx/blob/develop/v4/docs/01-jwt.mdhttps://github.com/lestrrat-go/jwx/blob/develop/v4/docs/02-jws.mdhttps://github.com/lestrrat-go/jwx/blob/develop/v4/docs/03-jwe.mdhttps://github.com/lestrrat-go/jwx/blob/develop/v4/docs/04-jwk.mdhttps://github.com/lestrrat-go/jwx/blob/develop/v4/docs/10-extensions.mdhttps://github.com/lestrrat-go/jwx/blob/develop/v4/docs/99-faq.md
- Examples repo — runnable usage patterns. The repo's
README.mdis a topical index that maps "what do I want to do" → "which*_example_test.gofile." Fetch the README first when looking for an example by topic; then fetch the linked file:https://github.com/jwx-go/examples/blob/develop/v4/README.md
When the user's question goes beyond the patterns in this skill (custom claim types, JWE recipients with per-recipient headers, nested JWS+JWE serializers, custom key providers, base64 backend swap, performance tuning), fetch from these sources rather than guessing.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 314 lines · 61 tokens per session scan A e8e9bcf280e9
jwx-guide-v4 is a skill published in the GitHub repository lestrrat-go/jwx (2,418 stars, last pushed 3d ago), licensed MIT. It adds 61 tokens to every session and 4,712 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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